JP6364847B2 - Main memory access control device, main memory access control system, main memory access control method, and main memory access control program - Google Patents

Description

  The present invention relates to a main memory access control device that receives an access command to a main storage device and controls execution of the access command.

  In a computer system, there are cases where unauthorized access to an access prohibited area in the main storage device is performed due to various faults, logic bugs in a program to be executed, or by a malicious user. For example, if the system information stored in the access-prohibited area is illegally rewritten due to such unauthorized access, the system may be down. Alternatively, when data is illegally read from the access-prohibited area due to such unauthorized access, there is a possibility that the processing may be terminated abnormally or a security problem may occur. Therefore, with the advancement of an advanced information society, there is an increasing expectation for technology for preventing such unauthorized access.

  As a technique related to such a technique, Patent Document 1 discloses an apparatus that detects an illegal write request to a write-protected area in a memory and stops processing indicated by the detected write request. . This apparatus also stores and outputs the content of the write process instructed by the unauthorized write request.

  Further, in Patent Document 2, access history information to a storage device is stored in a history storage device different from the storage device, so that the access history information is acquired even when the storage device is down. A system is disclosed that allows for this.

Japanese Unexamined Patent Publication No. 04-326440 JP 2011-164840

  The technique disclosed in Patent Document 1 can prevent unauthorized write access to the main storage device, but cannot prevent unauthorized read access. The technique disclosed in Patent Document 2 cannot prevent unauthorized read access to the main storage device. If data is illegally read from the access-prohibited area, there is a possibility that the process may end abnormally or a security problem may occur. Therefore, merely preventing unauthorized write access to the main storage device is insufficient in the operation management of the computer system.

  The main object of the present invention is to provide a main memory access control device, a main memory access control system, a main memory access control method, and a main memory access control program that solve this problem.

  The main memory access control device according to the present invention is issued to the main storage device, storage means capable of storing illegal access definition information defining command information that is illegal access, with respect to a read access command to the main storage device. The instruction information included in the read access instruction is compared with the unauthorized access definition information, and a detection unit that detects that the read access instruction is unauthorized access when a comparison result satisfies a predetermined condition; Execution control means for stopping execution of the read access instruction when the detection means detects that the read access instruction is unauthorized access.

  In another aspect of achieving the above object, the main memory access control method according to the present invention stores illegal access definition information that defines command information that is illegal access with respect to a read access command to the main memory by an information processing device. And the read access instruction issued to the main storage device is collated with the unauthorized access definition information, and the collation result satisfies a predetermined condition, the read access instruction Is detected as unauthorized access, and when it is detected that the read access instruction is unauthorized access, execution of the read access instruction is stopped.

  Further, in a further aspect of achieving the above object, the main memory access control program according to the present invention provides illegal access definition information that defines instruction information that is illegal access to a storage means for a read access instruction to the main storage device. The storage processing to be stored and the instruction information included in the read access instruction issued to the main storage device are collated with the unauthorized access definition information, and the read is performed when the collation result satisfies a predetermined condition. A detection process for detecting that the access instruction is an unauthorized access; and an execution control process for stopping execution of the read access instruction when the detecting means detects that the read access instruction is an unauthorized access. The computer is executed.

  Furthermore, the present invention can also be realized by a computer-readable non-volatile storage medium storing such a main memory access control program (computer program).

  The present invention makes it possible to prevent unauthorized reading of data from the main storage device.

1 is a block diagram showing a configuration of a main memory access control system according to a first embodiment of the present invention. It is a flowchart which shows operation | movement of the main memory access control system which concerns on 1st Embodiment of this invention. It is a figure which shows the example of the main memory unit address space based on 1st Embodiment of this invention. It is a figure which shows the structural example of the unauthorized access definition information which concerns on 1st Embodiment of this invention. It is a figure which shows the structural example of the log information which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the main memory access control apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the information processing apparatus which can execute the main memory access control apparatus which concerns on each embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram conceptually showing the structure of the main memory access control system 1 according to the first embodiment. The main memory access control system 1 according to the present embodiment includes a main memory access control device 10, a main memory device 20, a CPU (Central Processing Unit) 30, an IO (Input Output) controller 40, an external information processing device 50, and a system. A bus 60 is provided. Among these components, the components other than the external information processing device 50 are built in an information processing device such as a server device, for example. The main memory access control system 1 may include a plurality of CPUs 30, IO controllers 40, and external information processing devices 50, respectively.

  The main memory access control device 10, the CPU 30, and the IO controller 40 are communicably connected via a system bus 60. The CPU 30 accesses the main storage device 20 via the main storage access control device 10. The external information processing device 50 accesses the main storage device 20 via the IO controller 40 and the main storage access control device 10. The IO controller 40 is a card that controls an IO interface such as a PCI (Peripheral Components Interconnect) Express card.

  The main storage device 20 stores various data used when the CPU 30 and the external information processing device 50 perform information processing in a predetermined area for each data type.

  A configuration example of the main storage device address space 200 related to the main storage device 20 is shown in FIG. In the example shown in FIG. 3, the area from the address “0x00000000” (“0x” indicates hexadecimal notation) to “0x00FFFFFF” in the main memory address space 200 is the program code area 201. A program code relating to software executed by the CPU 30 is stored in the program code area 201. An area from the address “0x01000000” to “0x01FFFFFF” in the main storage device address space 200 is a control data storage area 202. In the control data storage area 202, data for controlling software executed by the CPU 30 is stored. The area where the address in the main storage device address space 200 is “0x02000000” or later is a data area 203. In the data area 203, for example, data that the external information processing apparatus 50 communicates with the CPU 30 is stored. The configuration of the main storage device address space 200 related to the main storage device 20 is not limited to the configuration shown in FIG.

  The main memory access control device 10 receives an access command to the main storage device 20 issued by the CPU 30 and the external information processing device 50, and processes the access command. As shown in FIG. 1, the main memory access control device 10 includes an unauthorized access definition information storage unit 11, a detection unit 12, and an execution control unit 13. The detection unit 12 and the execution control unit 13 may be electronic circuits or may be realized by a computer program and a processor that operates according to the computer program. The unauthorized access definition information storage unit 11 is a storage device such as an electronic memory or a magnetic disk in which access control is performed by an electronic circuit or a computer program and a processor that operates according to the computer program.

  The unauthorized access definition information storage unit 11 stores unauthorized access definition information 110. The unauthorized access definition information 110 is information serving as a reference when determining whether an access command to the main storage device 20 issued by the CPU 30 or the external information processing apparatus 50 is an unauthorized access command. The unauthorized access definition information 110 is registered in the unauthorized access definition information storage unit 11 by, for example, a system administrator who manages the main memory access control system 1. The unauthorized access definition information storage unit 11 may be a dedicated electronic memory or magnetic disk different from the main storage device 20 or may use a part of the main storage device 20.

  A configuration example of the unauthorized access definition information 110 is shown in FIG. The unauthorized access definition information 110 includes a record in which an entry 111, an offset address 112, an area size 113, a bus master 114, and an access type 115 are associated. The entry 111 is the item number of each record. The offset address 112 and the area size 113 are information indicating specific areas in the main storage device address space 200. For example, the area in the main storage device address space 200 in which the offset 111 is “0x00000000” and the area size 113 is “0x01000000” indicated by the record whose entry 111 is “1” is the program code area shown in FIG. This corresponds to 201. Further, the area in the main storage device address space 200 in which the offset 111 is “0x00000000” and the area size 113 is “0x02000000” indicated by the records whose entries 111 are “2” and “3” is shown in FIG. It corresponds to the program code area 201 and the control data storage area 202 shown.

  The bus master 114 is information indicating an output source that has output an access command to the main storage device 20 to the system bus 60. For example, the value indicated by the bus master 114 in the record whose entry 111 is “1” is “CPU30”. This indicates that the record defines an unauthorized access command with respect to the access command issued by the CPU 30. Further, the value indicated by the bus master 114 in the record having the entry 111 of “2” and “3” is “IO controller 40”. In the present embodiment, the IO controller 40 outputs an access command to the main storage device 20 received from the external information processing device 50 to the system bus 60. Therefore, this record indicates that an unauthorized access command is defined for the access command issued by the external information processing apparatus 50.

  The access type 115 is information for identifying whether an access command to the main storage device 20 is a write command or a read command.

  The record in which the entry 111 in the unauthorized access definition information 110 shown in FIG. 4 is “1” defines a write access from the CPU 30 to the program code area 201 in the main storage device address space 200 as an unauthorized access instruction. The reason is that the program code stored in the program code area 201 is not rewritten during normal operation. In addition, records in which the entry 111 in the unauthorized access definition information 110 is “2” and “3” are written from the external information processing apparatus 50 to the program code area 201 and the control data storage area 202 in the main storage device address space 200. Access and read access are defined as unauthorized access instructions. This is because the program code area 201 and the control data storage area 202 are areas used only when the CPU 30 performs information processing. That is, in the present embodiment, only the data area 203 is accessible to the external information processing apparatus 50 in the main storage device address space 200.

  The detection unit 12 receives an access command to the main storage device 20 issued by the CPU 30 or the external information processing device 50 via the system bus 60. The detection unit 12 collates the command information of the received access command with the unauthorized access definition information 110. The detection unit 12 detects records whose identifiers and access types that can identify the output source output to the system bus 60 included in the instruction information match the bus master 114 and the access type 115, respectively. When the access address included in the instruction information is included in the area determined by the offset address 112 and the area size 113 in the detected record, the detection unit 12 determines that the received access instruction is illegal to the main storage device 20. It is determined that it is an access instruction. The detection unit 12 notifies the execution control unit 13 that the access instruction is an unauthorized access instruction.

  If the access instruction is not an unauthorized access instruction, the execution control unit 13 executes the access instruction. If the detection unit 12 is notified that the access instruction is an unauthorized access instruction, the execution control unit 13 stops the execution of the access instruction. The execution control unit 13 generates log information 130 based on the instruction information of the access instruction.

  A configuration example of the log information 130 is shown in FIG. The log information 130 includes n (n is an integer equal to or greater than 1) and the log entries 131-1 to n. The log entry 131-1 includes a time stamp 1311-1, an access type 1312-1, a bus master 1313-1, an address 1314-1, and data 1315-1. The configuration of the log entries 131-2 to n is the same as that of the log entry 131-1.

The time stamp 1311-1 stores a value indicating the time when information is stored in the log entry 131-1. The access type 1312-1 stores a value indicating the access type included in the command information of the access command. The bus master 1313-1 stores an identifier that can identify the output source output to the system bus 60 included in the instruction information. The address 1314-1 stores a value indicating an access address included in the instruction information. Data 1315-1 stores write data in the write access included in the instruction information.

  The execution control unit 13 stores the generated log information 130 in a predetermined area in the main storage device 20, for example. Alternatively, the execution control unit 13 may store the log information 130 in another storage device other than the main storage device 20 in the main storage access control system 1.

  Next, the operation (processing) of the access control system 1 according to the present embodiment will be described in detail with reference to the flowchart of FIG.

  The detection unit 12 receives an access command to the main storage device 20 issued by the CPU 30 or the external information processing apparatus (step S101). The detection unit 12 collates the instruction information in the access instruction with the unauthorized access definition information 110 and confirms whether there is a record in the unauthorized access definition information 110 that matches the content of the instruction information. (Step S102).

  When there is no record that matches the content of the instruction information and the access instruction is not an unauthorized access instruction (No in step S103), the execution control unit 13 sends the main storage device 20 based on the instruction information in the access instruction. Access is made (step S104). The main memory access control device 10 transmits the access result to the main memory device 20 to the issuer of the access command (step S105), and the entire process ends.

  If there is a record that matches the content of the command information and the access command is an unauthorized access command (Yes in step S103), the execution control unit 13 stops the execution of the access command (step S106). The execution control unit 13 generates the log information 130 based on the instruction information in the access instruction, stores the generated log information 130 in a predetermined storage location (step S107), and the entire process ends.

  The main memory access control system 1 according to the present embodiment can prevent unauthorized reading of data from the main memory device. The reason is that the detection unit 12 detects an unauthorized read access instruction for the main storage device 20 based on the unauthorized access definition information 110, and the execution control unit 13 stops the execution of the detected unauthorized read access instruction. Because it does.

  There is a system in which write access to a specific area is not accepted in order to prevent data stored in a specific area in the main storage device from being illegally changed. However, there is generally no access restriction for read access from the main storage device. For this reason, as a result of the CPU reading out illegal data from the main storage device, there is a possibility that a result relating to information processing will be illegal or a system failure or the like may occur.

  On the other hand, in the main memory access control system 1 according to the present embodiment, the unauthorized access definition information storage unit 11 defines the unauthorized access command for the read access command in addition to the write access command for the main storage device 20. The unauthorized access definition information 110 is stored. Then, the detection unit 12 detects an illegal read access instruction, and the execution control unit 13 stops the execution of the detected illegal read access instruction. Thereby, the main memory access control system 1 according to the present embodiment can prevent data from being illegally read from the main memory.

  Further, the unauthorized access definition information 110 according to the present embodiment includes a record in which an area in the main storage device address space 200, an identifier that can identify the issuer that issued the access command, and a value that identifies the access type are associated with each other. Is included. Thereby, the main memory access control system 1 can flexibly set whether to permit access to the main storage device 20 for each access instruction issuer, each access area, and each access type. .

  Furthermore, when the detection unit 12 detects an unauthorized access command, the execution control unit 13 according to the present embodiment generates log information based on the command information of the unauthorized access command. In a general computer system, a system failure occurs as a result of data being destroyed due to unauthorized write access to the main storage device or as a result of performing information processing using unauthorized data due to unauthorized read access. When it occurs, start fault handling. However, it is difficult to identify the device that has made unauthorized access to the main storage device and the time that such unauthorized access has been made based on the log information collected in such failure processing. Further, when the program that performs the failure processing itself is destroyed due to such unauthorized access, the failure processing itself cannot be executed. When the main memory access control system 1 according to the present embodiment detects an unauthorized access instruction, the main memory access control system 1 stops execution of the unauthorized access instruction and generates log information based on the instruction information of the unauthorized access instruction. Such a problem can be avoided.

<Second Embodiment>
FIG. 6 is a block diagram conceptually showing the structure of the main memory access control device 70 of the second embodiment.

  The main memory access control device 70 according to the present embodiment includes a storage unit 71, a detection unit 72, and an execution control unit 73.

  The storage unit 71 stores unauthorized access definition information 710 that defines instruction information that is unauthorized access regarding a read access command to the main storage device 20.

  The detection unit 72 checks the command information included in the read access command issued to the main storage device 20 with the unauthorized access definition information 710. Then, the detection unit 72 detects that the read access instruction is unauthorized access when the collation result satisfies a predetermined condition.

  When the detection unit 72 detects that the read access instruction is unauthorized access, the execution control unit 73 stops the execution of the read access instruction.

  The main memory access control device 70 according to the present embodiment can prevent unauthorized reading of data from the main storage device. The reason is that the detection unit 72 detects an unauthorized read access instruction for the main storage device 20 based on the unauthorized access definition information 710, and the execution control unit 73 cancels the execution of the detected unauthorized read access instruction. Because it does.

<Hardware configuration example>
In each of the above-described embodiments, each unit illustrated in FIGS. 1 and 6 can be realized by a dedicated HW (Holdware) (electronic circuit). Further, at least the storage control function in the unauthorized access definition information storage unit 11 and the storage unit 71, the detection units 12 and 72, and the execution control units 13 and 73 are regarded as a function (processing) unit (software module) of the software program. be able to. However, the division of each part shown in these drawings is a configuration for convenience of explanation, and various configurations can be assumed for mounting. An example of the hardware environment in this case will be described with reference to FIG.

  FIG. 7 is a diagram exemplarily illustrating a configuration of an information processing apparatus 900 (computer) that can execute the main memory access control apparatus according to the exemplary embodiment of the present invention. That is, FIG. 7 shows a configuration of a computer (information processing apparatus) that can realize the main memory access control apparatus shown in FIGS. 1 and 6, and hardware that can realize each function in the above-described embodiment. Represents the environment.

  An information processing apparatus 900 illustrated in FIG. 7 includes a CPU 901, a ROM (Read_Only_Memory) 902, a RAM (Random_Access_Memory) 903, a hard disk 904 (storage device), and a communication interface 905 (Interface: hereinafter referred to as “I / F”). A reader / writer 908 capable of reading and writing data stored in a storage medium 907 such as a CD-ROM (Compact_Disc_Read_Only_Memory), and an input / output interface 909, which are connected via a bus 906 (communication line). General computer.

  Then, the present invention described by taking the above-described embodiment as an example, the information processing apparatus 900 shown in FIG. 7 is illegal in the block configuration diagrams (FIG. 1 and FIG. 6) referred to in the description of the embodiment. After supplying the storage control function in the access definition information storage unit 11 and the storage unit 71, the detection units 12 and 72, the execution control units 13 and 73, or the computer program capable of realizing the function of the flowchart (FIG. 2), This is achieved by reading the computer program into the CPU 901 of the hardware, interpreting it and executing it. The computer program supplied to the apparatus may be stored in a readable / writable volatile storage memory (RAM 903) or a nonvolatile storage device such as the hard disk 904.

  In the above-described case, the computer program can be supplied to the hardware by a method of installing in the apparatus via various storage media 907 such as a CD-ROM, or an external method via a communication line such as the Internet. A general procedure can be adopted at present, such as a method of downloading more. In such a case, it can be understood that the present invention is configured by a code constituting the computer program or a storage medium 907 in which the code is stored.

  The present invention has been described above using the above-described embodiment as an exemplary example. However, the present invention is not limited to the above-described embodiment. That is, the present invention can apply various modes that can be understood by those skilled in the art within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Main memory access control system 10 Main memory access control apparatus 11 Unauthorized access definition information storage part 110 Unauthorized access definition information 111 Entry 112 Offset address 113 Area size 114 Bus master 115 Access type 12 Detection part 13 Execution control part 130 Log information 131- 1 to n Log entries 1311-1 Time stamp 1312-1 Access type 1313-1 Bus master 1314-1 Address 1315-1 Data 20 Main storage device 200 Main storage device address space 201 Program code area 202 Control data storage area 203 Data area 30 CPU
40 IO Controller 50 External Information Processing Device 60 System Bus 70 Main Memory Access Control Device 71 Storage Unit 710 Unauthorized Access Definition Information 72 Detection Unit 73 Execution Control Unit 900 Information Processing Device 901 CPU
902 ROM
903 RAM
904 Hard disk 905 Communication interface 906 Bus 907 Storage medium 908 Reader / writer 909 Input / output interface

Claims (6)

Storage means capable of storing unauthorized access definition information defining instruction information that is unauthorized access with respect to an access instruction representing read access or write access to the main storage device;
The Kia access instruction the instruction information including the previous issued to the main storage device, the against the unauthorized access definition information, when the collation result satisfies a predetermined condition, incorrect pre Kia access instruction Detection means for detecting access,
When the detecting means detects that before Kia access instruction is illegal access, and execution control means to stop the execution of the pre Kia access instruction,
Equipped with a,
The execution control means outputs the instruction information included in the access instruction as log information when the detecting means detects that the access instruction is unauthorized access,
The log information includes write data for the main storage device by the access instruction representing the write access.
Main memory access controller. It said storage means indicates an address area in the main memory device before Kia access instruction is accessed, and stores a value indicating unauthorized access address area,
It said detecting means, the value of the instruction information indicates encompass access address, detects that said included in the unauthorized access address area,
The main memory access control device according to claim 1 . Wherein the storage unit, the pre-Kia access instruction can be identified to the issued publisher identifier, the associated value indicating unauthorized access address area, and stores the unauthorized access definition information,
When the value indicated by the access address included in the instruction information is included in the unauthorized access address area, the identifier included in the instruction information is associated with the unauthorized access address area. To detect that
The main memory access control device according to claim 2 . A main memory access controller according to any one of claims 1 to 3, having a said main storage unit, a main storage access control system. Depending on the information processing device,
With respect to an access instruction representing a read access or a write access to the main storage device, the unauthorized access definition information defining the instruction information that is unauthorized access is stored in the storage means,
The Kia access instruction the instruction information including the previous issued to the main storage device, the against the unauthorized access definition information, when the collation result satisfies a predetermined condition, incorrect pre Kia access instruction Detect access,
If the previous Kia access instruction detects that an unauthorized access, prior to abort the Kia access instruction,
When it is detected that the access command is unauthorized access, the command information included in the access command is output as log information,
The log information includes write data for the main storage device by the access instruction representing the write access.
Main memory access control method. A storage process for storing in the storage means unauthorized access definition information that defines instruction information that is unauthorized access with respect to an access instruction that represents read access or write access to the main storage device;
The Kia access instruction the instruction information including the previous issued to the main storage device, the against the unauthorized access definition information, when the collation result satisfies a predetermined condition, incorrect pre Kia access instruction A detection process for detecting access,
If the detection process detects that before Kia access instruction is illegal access, and executes control processing to stop the execution of the pre Kia access instruction,
To the computer,
The execution control process outputs the instruction information included in the access instruction as log information when the detection process detects that the access instruction is unauthorized access,
The log information includes write data for the main storage device by the access instruction representing the write access.
Main memory access control program.

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